For the purpose of a reduction in fuel consumption of a vehicle, an engine speed during idling of an engine is slowed down. As a result, a frequency spectrum of engine vibration during the idling includes a resonance frequency of a vehicle seat, which causes a decrease in drivability. In view of this, in recent years, such a seat has been developed that when an exciting force is transmitted to the seat, a headrest is caused to swing relative to a seatback in a front-rear direction, so as to damp vibration of the seat in the front-rear direction.
Patent Document 1 describes one example of a headrest support structure in which a headrest is elastically supported by a seatback. The support structure includes a tubular bracket provided in the seatback, and a support member that supports a tip portion of a headrest stay projecting from a headrest, and the support member is accommodated in an accommodation chamber of the bracket in a state where the support member can tilt in a front-rear direction. Further, springs are provided at two different positions in a regulation direction where the headrest stay extends, between an outer surface of the support member and an inner surface of the bracket. When an exciting force is transmitted to a seat, the headrest swings relative to the seatback around a fulcrum set between the springs in the regulation direction, so as to damp vibration of the seat.